DOI

https://doi.org/10.48717/b6z6-6x95

Project

EK052

Title

Identifying the g-factor of 6.7 GHz methanol maser

Abstract

Cosmic masers enable us to estimate the magnetic field via the Zeeman effect, especially in high-mass star-forming regions where OH and methanol masers occur. We can measure the Zeeman-splitting of the maser lines and, knowing the Landé g-factor, determine the strength of the magnetic field. The g-factor is undoubtedly known for the excited OH maser, but for methanol masers, it is still under investigation because it is still unclear which of the eight hyperfine transitions (each with its own g-factor) dominates the 6.7 GHz maser emission. To resolve this issue, we propose simultaneous observations of the 6.035 GHz exited OH and of the 6.7 GHz methanol maser emissions for two bright sources. We know, from our previous ex-OH and methanol maser observations, that in these two sources both maser emissions arise in the same spatio-kinematical regions and have clear Zeeman-splittings. Simultaneous observations of both maser lines will then allow us to compare the magnetic field estimated with the ex-OH masers with the Zeeman-splitting measured in the methanol maser line and to figure out the dominant hyperfine transition of the 6.7 GHz methanol maser.